On the 150th anniversary of Canada’s confederation, July 1, 2017, the National Arts Centre (NAC) in Ottawa, Ontario, raised the curtain on the first phase of a $110 million renovation and restoration project designed by Toronto-based Diamond Schmitt Architects (DSA). Adding 60,000 square feet of new space, the project brought the total size of the arts complex to 1.1 million square feet.
Designed by Canadian-Polish architect and theater designer Fred Lebensold, the original 1969 building was Brutalist in style with repeating hexagonal geometries in both its floor plan and finishes, such as the lobby ceiling’s triangular concrete coffers, tessellated to create a hexagonal pattern. However, the structure’s windowless concrete façade offered little in terms of the public realm. “When you’re in the parliamentary precinct … looking back to the city, you see the NAC, except it’s so mute, dark, and windowless that it almost looks like [part] of the landscape,” says DSA principal in charge Don Schmitt, AIA.
How to update Brutalist architecture for today’s needs is a question architects are increasingly facing. To preserve the original NAC building but reorient it to its surroundings, DSA wrapped the northwest side of the building with a new multistory lobby, complete with a ceiling that draws from the hexagonal forms of the original lobby, but interpreted in wood.
Designed in Autodesk Revit by DSA, the coffers are arranged on a 10-foot equilateral triangle grid, forming hexagons that total 20 feet across. Each triangular coffer comprises three 9.5-foot-long, 3.1-inch-thick glulam members, with slightly rounded edges at their vertices to blur any misalignment. Members taper in depth from 4.25 feet to 3 feet, from the hexagons’ centers to their perimeters to create a sense of undulation. “The coffers themselves are not connected to one to another except by small pieces of blocking, approximately 10 inches square, maintaining the 150-millimeter [visual] gap between the coffers,” says Will Loasby, senior project manager at structural engineering firm Fast + Epp, in Vancouver.
DSA’s choice of wood stemmed in part from its desire to celebrate Canada’s vast forests and to showcase a domestic product—glulam made from Douglas fir trees grown in British Columbia. Wood is also a warm, “natural material used in a natural state,” Schmitt says.
Moreover, the wood ceiling could be prefabricated off-site. The NAC had set an aggressive 18-month construction schedule to reach completion on the country’s 150th anniversary. Prefabrication would considerably expedite construction.
On the outskirts of Ottawa, timber engineering and construction firm StructureCraft Builders, based in Abbotsford, British Columbia, transformed a warehouse into a temporary production facility, in part to reduce transportation costs. Once workers assembled the triangular coffers off-site, they raised the panels to install lighting and electrical conduit using notches cut into the top edges of the glulam members, which DSA designed with Fast + Epp. Triangular acoustic ceiling panels would conceal the services from below.
The triangular coffers were assembled and trucked to the site in long, linear panels of up to 12 coffers, the largest of which measured 65 feet and weighed 30,000 pounds. The panels alternate the orientation of adjacent triangles 180 degrees so that, when hung, they create a field of hexagons. A Y-shaped steel plate ties the coffers into the building’s glulam-timber-and-steel structure.
With help from a custom glass curtainwall with transparent LED screens that transform the building’s façade into what Schmitt calls a “fifth stage,” the addition’s exposed wood structure creates a diaphanous layer between the intimacy of the NAC and the bustle of the city. In a sense, the architects turned the building inside-out, a move occurring more frequently in performing arts venues around the world, Schmitt says. No longer relegated to ticket-taking and coat-checking, lobbies are become extensions of both the venue and the street, creating a third space in which the two are overlaid.
Notably, DSA’s expansion and renovation also defers to the NAC’s historical architecture, using new materials in ways that honor Lebensold’s original design intent. “We didn’t demolish anything,” Schmitt says. “We retained and preserved all of it.”
Shortly after the NAC reopened, Schmitt himself had a chance to observe the space in action, attending a lecture on architecture. Afterward, the lobby transformed into a quasi-street fair, with food stalls manned by some of the city’s top chefs and an array of musical performances, from jazz to a singer-songwriter. When Schmitt finally pulled himself away to leave, around 11 p.m., he was astounded by what he saw: more people newly arriving.